The present disclosure generally relates to an antisense approach to prevent and/or reverse an autoimmune diabetes condition in NOD mice. This includes microsphere delivery of AS-oligonucleotides by injection to achieve therapeutic effect that causes a negative modulating activity, particularly in the non-obese-diabetic (NOD) mouse model. The microspheres are fabricated using totally aqueous conditions, which microspheres incorporate one or more antisense (AS) oligonucleotides.
Microparticles, microspheres, and microcapsules are solid or semi-solid particles having a diameter of less than one millimeter, and may be less than 100 microns, which can be formed of a variety of materials, including synthetic polymers, proteins, and polysaccharides. Microspheres have been used in many different applications, primarily separations, diagnostics, and drug delivery.
A number of different techniques can be used to make these particles from synthetic polymers, natural polymers, proteins and polysaccharides, including phase separation, solvent evaporation, emulsification, and spray drying. Generally the polymers form the supporting structure of these microspheres, and the drug of interest is incorporated into the polymer structure. Exemplary polymers used for the formation of microspheres include homopolymers and copolymers of lactic acid and glycolic acid (PLGA) as described in U.S. Pat. No. 5,213,812 to Ruiz, U.S. Pat. No. 5,417,986 to Reid et al., U.S. Pat. No. 4,530,840 to Tice et al., U.S. Pat. No. 4,897,268 to Tice et al., U.S. Pat. No. 5,075,109 to Tice et al., U.S. Pat. No. 5,102,872 to Singh et al., U.S. Pat. No. 5,384,133 to Boyes et al., U.S. Pat. No. 5,360,610 to Tice et al., and European Patent Application Publication Number 248,531 to Southern Research Institute; block copolymers such as such as Tetronic®908 and poloxamer 407 as described in U.S. Pat. No. 4,904,479 to Illum; and polyphosphazenes as described in U.S. Pat. No. 5,149,543 to Cohen et al. Microspheres produced using polymers such as these exhibit a poor loading efficiency and are often only able to incorporate a small percentage of the drug of interest into the polymer structure. Therefore, substantial quantities of these types of microspheres often must be administered to achieve a therapeutic effect. In addition, these polymers typically are hydrophobic, negatively impacting the dissolution of the drug of interest. Polymers typically used in this context include polylactic glycolic acid (PLGA).
An objective for the medical community is the delivery of nucleic acids to the cells in an animal for treatment of various diseases including diabetes. In many approaches, nucleic acids can be delivered to cells in culture (in vitro) relatively efficiently with the addition of transfection agents. In addition, in vivo, the presence of endogenous nucleases results in a high rate of nucleic acid degradation when nucleic acid is delivered to animals.
In addition to protecting nucleic acid from nuclease digestion, a nucleic acid delivery vehicle must exhibit low toxicity, must be efficiently taken up by cells and have a well-defined, readily manufactured formulation. As shown in clinical trials, viral vectors for delivery can result in a severely adverse, even fatal, immune response in vivo. In addition, this method has the potential to have mutagenic effects in vivo. Delivery by complexing nucleic acids in lipid complexes of different formulations (such as liposomes or cationic lipid complexes) can have toxic effects. Complexes of nucleic acids with various polymers or with peptides have shown inconsistent results and the toxicity of these formulations has not yet been resolved. Nucleic acids also have been encapsulated in polymer matrices for delivery, but in these cases the particles have a wide size range and the effectiveness for therapeutic applications has not yet been demonstrated. Such previous approaches can yield effects that are the opposite of a goal desired herein, including stimulation of the immune system. For example, when PLGA is incorporated into particles, the immune system is stimulated by the presence of the PLGA.
Therefore, there is a need for addressing the issues in the delivery of nucleic acids, and there is an ongoing need for development of microspheres and new methods for making microspheres. Details regarding microspheres, especially details regarding their preparation and properties, are found in U.S. Pat. Nos. 6,458,387 to Scott et al., 6,268,053, 6,090,925, 5,981,719 and 5,599,719 to Woiszwillo et al., and 5,578,709 to Woiszwillo and U.S. Patent Application Publication No. 2006/0024240 to Brown et al. These and all references identified herein are incorporated by reference hereinto.